Process of purifying para-nitraniline



Patented June 12, 1928.

ALFRED MILLER, OF BUFFALO, NEW YORK, ASSIGNQB '1'0 00., INC., A CORPORATION 01'' NEW rowan murao'runme You.

PROCESS O F PUBIFYING PARA-NITBANEINE.

- No mawag. Application filed July 14, 925, Serial 11043518. Renewed mm :5, 1m

Y This invention-relates to a new process of purifying or treating nitraniline, specifically para-nitraniline. In the manufacture of para-nitraniline from para-mt-ro-chlor- 5 benzene with-ammonia under pressure, certain by-products are formed. as described by'Ullman. Enzyklopadie der technischen Chemie. vol. 1, page 440, and these have the efiect of causing a fiocculent precipitate to form when the nitraniline is diazotized.

It is an object of this invention to prevent the formation of such precipitate and thus 'to purify the nitraniline by a suitable treatment with a reducing agent or its equivalent.

5 In accomplishing this result I treat the nitraniline with either a neutral, acid or al-. kaline reducing agent in suitable pro ortions at an elevated temperature. as more ully describedin'the following examples.

One hundred 'and sixty parts of-crude para-niti'aniline are suspended in 2800 parts of water. 6 to 8 parts of sodium sulphide .erystals are dissolved in 200 parts of Water may be present. Thesolut-ion of sodium sulphide is added to the suspension of paranitraniline and the charge is heated up to 95 to l00 C. with constant agitation. It is then cooled to 40 to 45C., filtered, and washed with water. The resulting para-nitraniline gives a clear diazo solution.

As a second example, I suspend 160 parts of'crude ara-nitraniline in 2500 parts of water and then add a solution of ammonium sulphide containing 2 to 2 parts of 100% ammoniumsul hide. The liquid is heated to 90 to 100 thereafter cooled to 30 to 35 (3.; filtered, and washed well.

As another example, I take 160 parts of crude para-nitraniline, suspend it in 2500 parts of water and 2 parts of stannous chloride, and add 2 parts of ammonium chloride. The temperature is raised to 80 to 90 C. while the solution is agitated and it is thereafter again cooled to 30 to 35 C., filtered and washed.

A still further example consists in taking 160 parts of crude para-nitraniline suspended in 3000 parts of water, and adding 2 to 3 parts of stannons chloride and 2 to 3 parts of commercial muriatic acid of Be. density.- The solution is heated to 80 to 90 C., cooled to to (3., filtered 'mean to and filtered "free from any sediment which "a fiocculent. precipitate and washed. The para-nitraniline obtained solution free from any,

gives a clear diazo flocculent precipitate. v

In these exam les I have named mild re ducing agents which reduce the nitro bodies or other impurities present but which do not affect the nitraniline molecule itself,-that is to say, there is no reduction of the N0 group attached to the benzene nucleus. The" quantity of reducing agent employed is proportioned to the amount of impurity resent. By mild reducing agent in the caims I include the above described dilute reducing agents and their have: the herein described c act. ess can be applied to nitraniline from whatsoever source derived and it ma also be applied at any suitable point in t e manufacture of nitraniline.

As various embodiments of the invention may be made without departing from the principle thereof it isto be understood that do not limit myself to the foregoing embodiments except as defined in the following claims.

I claim:

1. In the manufacture of nitraniline from nitro-c-hlor-benzol with ammonia wherein certain by-products are formed which cause a fiocculent precipitate upon diazotization the process characterized by'reducin sai by-productsby 'means of a mild reducing agent.

2. In the manufacture of nitraniline from nitro-chlor-benzol with ammonia wherein certain by-products are formed which causes upon diazotigation, the process characterized by reducing said byroducts by means of: stannous chloride in ilute solution. I

3. Int-he manufacture of nitran'iline from nitro-chlor-benzol with ammonia wherein certain by-products are formed which cause uivalents, which The proca fiocculent precipitate upon-diazotization f the process characterized by reducing said by-products with stannous chloride in dilute aqueous solution, heatin to a temperature below-boiling and thereai ter filtering 03 the solution from the nitraniline."

In testimony that I claim the fpregoing, I have hereunto set my hand this 10th July, 1925.

ALFRED MILLER.

day of 

